GOP presidential candidate Donald Trump unveiled Monday the latest version of his plan to overhaul the American tax code, offering relief for everyone from parents paying for child care to the world's largest corporations.

But it remains to be seen where the money will come from to pay for those cuts.

Details of the plan are still fairly sketchy, but in his speech at the Detroit Economic Club, Trump promised they would be forthcoming soon.

"In the coming weeks we will be offering more detail on all of these policies," Trump said Monday.

The Trump campaign has promised that the tax plan would "benefit working families while ensuring the wealthy pay their fair share." But based on details of Trump's plan released earlier in the campaign, some analysts think the biggest winners would be those at the top of the income ladder.

"The proposal would cut taxes at every income level, but high-income taxpayers would receive the biggest cuts, both in dollar terms and as a percentage of income," according to an analysis in December by the Tax Policy Center.

But based on the details released so far, the plan would also explode the federal budget deficit, add trillions of dollars to the national debt and substantially raise the government's interest payments, according to several independent analysts.

Trump's tax cuts would amount to some $12 trillion over the next decade, according to the Tax Foundation. Even after accounting for stronger economic growth, the plan would leave the government more than $10 trillion short over the next 10 years. That money would have to be made up for with more borrowing, dramatically expanding the nation's debt.

Trump also promised to ease the burden on American corporations by limiting taxes to 15 percent. The campaign has also promised to "make our corporate tax globally competitive and the United States the most attractive place to invest in the world."

Based on the latest available data, that promise should be fairly easy to keep.

While the top federal tax rate on corporate profits is 35 percent, American companies pay far less, thanks to a thicket of deductions and loopholes in the tax code.

Between 2006 and 2012, at least two-thirds of all corporations had no federal income tax liability, according to a study earlier this year by the General Accountability Office.

Among large corporations (those with at least $10 million in assets), less than half paid no federal income tax in 2012. Between 2008 and 2012, large corporations with profits paid, on average, federal taxes amounting to just 14 percent of their net income, according to the GAO.

When foreign, state and local income taxes are included, the average effective tax rate came to just over 22 percent, the study found. Of course, a Trump administration would have little or no control over taxes levied by states, municipalities and foreign governments.

As for the level of corporate taxes, they compare favorably with the rest of the world. Of the 28 advanced economies in the Organization for Economic Co-operation and Development, the U.S. ranks 16th in corporate taxes when measured as a share of gross domestic product, according to OECD data. That's below the average level for the group.

As for making the U.S. attractive to investors, Trump won't have to do anything to keep that promise. The United States is already the most attractive place to invest in the world, by far.

Last year, the U.S. led the world with some $420 billion in total net inflows of foreign direct investment, according to the World Bank. That figure includes all the money foreign investors put to work in the U.S. (including equity capital and reinvestment of earnings).

China came in second, with $250 billion, followed by Hong Kong ($181 billion), Ireland ($126 billion) and Switzerland $120 billion.

Trump unveiled some new details Monday, including a pledge to exclude all child-care expenses from taxation. That would create a substantial tax break for working parents, but further widen the deficit.

On average, households with a woman working outside her home and taking care of a child under 15 paid an average $127 a week on child care, according to a Census Bureau analysis of 2010 data. That works out to about $6,600 a year. With some 24 million households in that category, the child-care tax break would cost the government $158 billion a year.

For families paying for child care, the current tax break offers little relief. Only 3.5 million tax returns claimed the existing child-care tax credit for the 2010 tax year, according to IRS data, saving those households $1.9 billion. (Nearly 10 million returns claimed a separate tax credit for all parents, whether or not the family had child-care expenses, for another $14 billion in tax savings.)

So total out-of-pocket child-care costs amounted to about $142 billion, which a Trump administration would either have to make up with higher taxes or add to the budget deficit.

Trump also wants to eliminate the estate tax, which generally applies to inheritances of more than about $5.5 million (or nearly $11 million for couples). Opponents of the tax argue that it hurts multigeneration small businesses by imposing an unsustainable burden on the transfer to the next generation.

But that burden is vastly overstated, according to some analysts. The current exclusion means that only the wealthiest 0.2 percent of Americans owe any estate tax when they die, according to the Center on Budget and Policy Priorities.

While a handful of wealthy families would benefit, according to the CBPP, eliminating the estate tax would cost $269 billion in lost revenues over the next decade, adding $320 billion to the federal deficit when additional interest on the national debt is accounted for.

Monday's speech was light on details about how Trump's proposed sweeping tax cuts would be paid for. But an earlier version of the tax-reform page on his website promised his plan would be "revenue neutral," based on a series of revenue-raising measures.

Those include eliminating unspecified tax breaks "available to the very rich," such as limiting itemized deductions, exemptions on life insurance interest and the so-called "carried interest" treatment of income for high-income earners.

Trump has also proposed a one-time tax on corporate cash stashed overseas to avoid U.S. taxes, which he estimates amounts to some $2.5 trillion, and elimination of other corporate deferrals on income earned overseas. He has also proposed unspecified cuts or elimination of "corporate loopholes that cater to special interests" and other corporate tax deductions.